We got some cast gun pieces to anodize this past weekend. We've had some success with cast in the past, but this was a total disaster this time as we didn't even get to try to anodize. We put them in cleaner and they got smutty as expected, then to the deox and it wouldn't toucht the smut.... but it could be wiped off. So we wiped them down and we put them in stripper for a few minutes as they were bead blasted and that seems to help in most cases. But when doing so... the parts reacted severely to the stripper solution. We thought it was a bit odd, but carried on. Back to the deox to remove smut and nothing. Didn't even touch it. One piece in particular started flakng stuff off in the deox... that was really odd. took that one out quite quickly and noticed that sploches of areas had smut and other didn't... hence the flakes. Ok apparently something was on the out side (almost like a plating). Back to the bead blaster to remove the remaining covering. then tried stripping and the reaction was much more normal. So we eventually try to stick this piece in the anodize solution and there is a violent reaction almost like sticking aluminum in a hot black oxide tank. So we're scratching the attempt at anodizing these pieces. It's really disappointing as we have a .22 short barrel that would have looked real nice in anodize. Now we have to resort to painting.
So anyway my question if anyone has any idea is what is in this alloy that reacts to a sulfuric acid solution this way? When I feel the weight of the piece in my hand it seems heavier than aluminum so I did some rough weight calculations with water displacement to try to make sure that it wasn't steel and if I did them right... it confirmed that it was not steel alloy but it feels like there is something more dense than aluminum in it as it feels heavier than I think it should. Not very scientific, but it's all I got.
So anyway my question if anyone has any idea is what is in this alloy that reacts to a sulfuric acid solution this way? When I feel the weight of the piece in my hand it seems heavier than aluminum so I did some rough weight calculations with water displacement to try to make sure that it wasn't steel and if I did them right... it confirmed that it was not steel alloy but it feels like there is something more dense than aluminum in it as it feels heavier than I think it should. Not very scientific, but it's all I got.
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